Re: completely hide parts of the partition table from Windows?

From: Mikael Pettersson
Date: Tue Aug 18 2009 - 19:56:27 EST


Andries E. Brouwer writes:
> On Tue, Aug 18, 2009 at 11:22:30PM +0200, Mikael Pettersson wrote:
>
> > So what I'm looking for is some sub-partition table format with the
> > following two properties:
> > 1. resides in an msdos partition entry of a type that Windows does
> > not inspect (for whatever extended partitions or Apple/BSD/Sun
> > stuff that Windows may have been taught to recognize)
> > 2. the locations and sizes of the sub-partitions are NOT limited by
> > the parent msdos partition entry
>
> The reason I added type 85 = LINUX_EXTENDED_PARTITION
> was precisely your concern: it should be something
> that DOS/Windows doesnt know about.
>
> > I've looked at the code in fs/partitions/msdos.c, and it seems that
> > most of the extended/BSD/Sun formats don't give me property #2 above.
>
> The standard description of extended partitions says that the size field
> of the parent extended partition descriptor is irrelevant, only the
> starting sector matters.
>
> If you look at the parse_extended() code in msdos.c you'll see
> that it does not use its parameter first_size.
> (Except in a certain case that you will not be in.)

Right. I misread the "process the data partitions" part to imply
that the limits were enforced for all four entries, not just the
last two usually-junk entries. Thanks for clarifiying that.

> Make a table that has a Linux extended partition (type 85)
> that is short enough not to cause Windows to worry. Have logical
> partitions inside of any size and location you desire.

I have created extended partitions with non-default type
(though not 85). I'll see if I can convince fdisk or parted to
create one with entries exceeding the parent's limits.

Thanks,

/Mikael
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